new: className in subclass constructor

[dblythy]

Hi,

Let's say you want to create a global function getName on all your Parse.Objects. Let's say you have 4 different classes. Here's how you'd have to do that now:

class ClassOne extends Parse.Object {
  constructor() {
    super('ClassOne');
  }
  getDetails() {
    return `${this.get('title')} ${this.get('description')}`;
  }
}
class ClassTwo extends Parse.Object {
  constructor() {
    super('ClassTwo');
  }
  getDetails() {
    return `${this.get('title')} ${this.get('description')}`;
  }
}
class ClassThree extends Parse.Object {
  constructor() {
    super('ClassThree');
  }
  getDetails() {
    return `${this.get('title')} ${this.get('description')}`;
  }
}
Parse.Object.registerSubclass('ClassOne', ClassOne);
Parse.Object.registerSubclass('ClassTwo', ClassTwo);
Parse.Object.registerSubclass('ClassThree', ClassThree);

Now, obviously this doesn't apply to all use cases, but this allows a registeredSubclass to have multiple class names, meaning that you can create one overhead class for multiple Parse Objects.

class ParseHelper extends Parse.Object {
  constructor(className) {
    super(className);
  }
  getDetails() {
    return `${this.get('title')} ${this.get('description')}`;
  }
}
const classNames = ['ClassOne', 'ClassTwo', 'ClassThree'];
for (const className of classNames) {
  Parse.Object.registerSubclass(className, ParseHelper);
}

[codecov]

Codecov Report

Merging #1315 (cbae1c4) into master (29fc171) will not change coverage.
The diff coverage is 100.00%.

@@            Coverage Diff            @@
##            master     #1315   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           60        60           
  Lines         5851      5847    -4     
  Branches      1314      1312    -2     
=========================================
- Hits          5851      5847    -4     

Impacted Files	Coverage Δ
src/ParseObject.js	100.00% <100.00%> (ø)

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[dplewis]

Can you write a failing test? I kinda know what you are trying to do.

[dblythy]

Can you write a failing test? I kinda know what you are trying to do.

Yes, the main problem is that subclassing doesn't work without super(ClassName), and ClassName has to be, the specific object's class name.

it('can use on ParseObject subclass for multiple Parse.Object class names', () => {
  class MyParseObjects extends ParseObject {
    constructor() {
      super();
    }
  
    doSomething() {
      return 5;
    }
  
    static readOnlyAttributes() {
      return ['readonly', 'static', 'frozen'];
    }
  }
  ParseObject.registerSubclass('TestObject', MyParseObjects);
  ParseObject.registerSubclass('TestObject1', MyParseObjects);
  ParseObject.registerSubclass('TestObject2', MyParseObjects);
  const obj = new MyParseObjects('TestObject');
  expect(obj.className).toBe('TestObject');
  const obj1 = new MyParseObjects('TestObject1');
  expect(obj1.className).toBe('TestObject1');
  const obj2 = new MyParseObjects('TestObject2');
  expect(obj2.className).toBe('TestObject2');
});

[dplewis]

Just a quick nit. Nice catch!

[dblythy]

Thanks @dplewis! Will be very helpful for me on Vue projects.

Note that this will have implications for #924

[dplewis]

I’m surprise nobody caught this. Should look into #924